Reviews > Lighting > Lanterns > Brunton Liberty Mantleless Lantern > David Sowards-Emmerd > Initial Report

Initial Report - Brunton Liberty Mantleless Lantern
March 4, 2005

Backpacking Background:
I began backpacking semi-frequently about four years ago, soon after moving to California. I generally take weekend (1 night) trips, and occasionally take 3-4 day trips. Most of my backpacking is at moderate altitude, 6,000'-12,000' (1,800-3,650 m), in conditions ranging from dry desert to hail/heavy snow in the mountains. In winter and spring, I split time between Southern California (SoCal) deserts and snowshoeing/skiing/snowcamping in the Sierra/Cascades. Summer and fall I tend to stick to the high country. I have reduced my packweight down to less than 50 lb (23 kg) over the past year - including food/water and a bear barrel. I'm trying to include more mountaineering, climbing and bouldering in my trips.

The Liberty was received on March 1, 2005.

Product Description:

Manufacturer's Specifications:
''

• 4'' x 2.5'' x 1.3'' (10.2 cm x 6.4 cm x 3.3 cm)
• 8.3 oz (235 g)
• Fuel: Isobutane
• Rating: Approximately 80 watts / 30 candlepower
• Burn time: Up to 6 hours at high output (one 8 oz canister)
• Platinum element instead of traditional mantles
• No fragile glass or plastic components
• Piezo electric ignition
• Built-in reflectors'aim the light exactly where you need it
• Includes durable nylon case
• Limited lifetime warranty''

Manufacturer's Warnings and Cautions: (no other place to get these than inside the packaging so far as I can tell)
''

• This product is for outdoor use only. DO NOT use this product indoors or in a vehicle, tent, camper or any other enclosed space.
• Keep the lantern away from the reach of children.
• Never use this unit for any purpose other than providing light.
• Never light or use this product near flammable materials.
• Never Cover the product and/or the fuel canister.
• Never leave the unit unattended while it is in use.
• Never touch the platinum element. The element can be easily bent or damaged. A damaged element may cause improper burning and may result in fire, burns and/or fatal injuries.
• Avoid placing any body parts over the unit while igniting or while the unit is in use.
• Changes in pressure at high altitude and temperature may cause difficulty with the Piezo ignition system. Be certain to always carry matches or a lighter as a backup.
• Use Bruntane fuel canisters only.
• Never attempt to disassemble the unit. This will void the warranty.
• Never store the unit with the fuel canister attached.
• Always keep the unit clean, free of the dust.''

Specifications (as measured by me):
Weight (Lantern only): 7.1 oz / 200 g
Weight (Case): 2.1 oz / 58 g
Dimensions of Case: 5.12'' x 2.75'' x 2'' (13 cm x 7 cm x 5 cm)
Dimensions of Lantern (folded): 4.25'' x 2'' x 1.25'' (10.8 cm x 5 cm x 3.2 cm)

Initial Impressions:

The Liberty arrived in standard store packaging: lantern, case, and two small instruction booklets (English and French). The size, weight, and quality of construction are about what I expected from the description on the manufacturer's website (I will discuss the performance of the lantern in my Field Report. The lantern is constructed of stainless steel (machined for the reflectors), cast bronze, and heat resisting resin. Attached is a Piezo igniter for lighting the lantern under normal conditions - this igniter generates a spark by applying a sharp pressure or shock to a crystal inside. The 'mantle' in the Liberty is a platinum catalyst in the form of a mesh dome. It is protected underneath by a inner wire dome, and above by an array of thick stainless steel wire and the 'sparker' portion of the Piezo igniter. Below the catalyst is what looks like a machined heat sink (the first indication that much of the energy is given off as heat). Below the heat sink is a valve that allows for the air intake to be regulated and at the base is the oversize (read: glove friendly) fuel regulator. Two reflectors, one on each side of the catalyst, adjust horizontally to focus the light to some degree. These fold in parallel and form the protective barrier for the lantern along with a protective piece of metal on top that latches together with the fuel regulator handle (see photo). These reflectors are also the recommended place to grasp the lantern when attaching a canister. The nylon case (see photo) is good and sturdy, but a bit on the heavy side as it weighs more than a quarter of what the lantern weights.

As recommended, I actually read the entire instruction booklet first instead of just tinkering with it like I usually would with a new toy. Then I grabbed a canister of fuel from the gear closet and began my first attempt at burning the house down. Unlike canister stoves, the liberty has an air intake adjustment as well as a fuel flow adjustment. There have to be at least two steps to the process if there are two switches. First, as per the instructions, I screwed on the fuel canister securely to the lantern - it's actually very secure due to a second rubber gasket directly between the lantern and the canister in addition to the standard rubber O-ring (see photo). Next, I switched the air intake to the lowest setting (it doesn't seal off completely), otherwise the mixture is too air rich and the Piezo won't ignite the gas. Next step is to turn on the gas a bit, and click the Piezo to ignite it. At this point, it burns blue above the platinum catalyst. The next step is to tweak the fuel/air mixture, and it is at this point that the catalyst starts to work, and begins glowing orange/yellow. The amount of fuel fed through seems to determine just how much of the catalyst is glowing (the lower edge does not shine until the fuel flow is around the maximum). The final step is then balancing the fuel/air mixture for maximum brightness, and obviously I need to adjust the air flow setting if I readjust if the fuel flow.

Also worth noting, I am able to ignite an air rich mixture with a lighter and in this case the catalyst begins glowing instantly - bypassing the blue flame stage.

Specific Things to Test:

• How useful is the Liberty for (carefully) warming up cold hands?
• Are there any noticeable effects of wind and/or cold on performance?
• What is the 'cool down' timescale under a couple sets of conditions?
• How easily are the reflectors scratched, and will this noticeably effect performance?
• Claimed light output: I'd guess more than half of the light output of the Liberty is in infrared (nice for heating, useless for the naked eye). I'll try to quantify this by taking a spectrum if I get a chance - it should be a simple blackbody. Also, I'll take some photos of the lantern alongside a standard incandescent bulb - from my initial tinkering, 80 watts doesn't seem like it is even in the right ballpark unless a very significant fraction is just the heat.
• How does the color of the light change as the fuel rate is changed? I'll include photos of this in future reports.
• Check on burn time: I'll see how much weight in fuel is burned in a short time under normal conditions and extrapolate that to the 6 hour claim (obviously there will be effects due to the decreased pressure in the canister, but I will ignore that.
• What is the range of brightness?
• How useful are the reflectors for adjusting the focus of the light?
• Stormproof? Will the lantern fail in a downpour or light rain?
• Does the Liberty have the same problem as canister stoves at cold temperatures?
• Under what conditions does the Piezo fail to ignite the lantern?
• Durability: Will the hinges loosen/tighten on the reflectors? Will the threads strip? Will the catalyst hold up, etc.?
• Stability: Will stability be a problem with small canisters?
• Is the light output great enough to be at all useful during a full moon?
• Easy to operate with gloves on?
• Easy to ignite in the dark (just by feel)?
• Will rust develop? I will do my best to store dry, but during the winter, the humidity/condensation can be a problem in my apartment (I don't use heat).
• How windproof is it once running? Can it be lit in strong winds with the Piezo? What about with a lighter? I'll use a fan for this at home as well as testing this in the field.
• The FAQ on the manufacturer's website claims the orange glow of the lantern will attract far fewer insects than white light. I'll report on any insect invasions once mosquito season rolls around.

FYI - Fuels (contradiction):

• Printed Instructions: only use with Bruntane fuel
• FAQ online: We recommend using Brunton or other high quality fuel canisters such as Primus or MSR. Lower grade brands may not allow the platinum element to glow.

Testing Locations and Test Plan:

I plan to test the Liberty on a handful of ski and snowshoe overnighters in the Sierra Nevada and southern Cascades as well as several warm overnighters. Generally, I expect to use the Liberty for lighting up camp and kitchen, but I'm sure it's got some other uses, like warming up cold hands. Hopefully, I'll also be able to use the Liberty for some night bouldering in the eastern Sierra this summer - if it's bright enough. As I'm currently applying for jobs, I can't be very specific about plans for this summer, but one possibility is taking the summer off and taking a long roadtrip with lots of backpacking along the way. In any case, the Liberty will get a thorough workout over the next six months.

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Reviews > Lighting > Lanterns > Brunton Liberty Mantleless Lantern > David Sowards-Emmerd > Initial Report